Compact Dual Polarization Feeding System of HY-2 Calibration Radiometer

A new double-septums in main wave guide and single septum in side waveguide ortho-mode transducer (OMT) is proposed in this paper. Finite difference method in time domain (FDTD) and genetic algorithms (GAs) are combined to analysis and optimize this new OMT. The simulation results of the OMT together with the feed horn validate the better characteristics of the new OMT than that of the common structure. The VSWR of this OMT is less than 1.1 in the bandwidth, the cross-polar level of the feed can reach -25 dB, while the length of the main waveguide can be reduced at least 30%. On the other hand, in order to reduce the weight and length of the feed, a compact conical corrugated horn is also employed.